Development of a percutaneous access device (PAD) which satifies long-term performance criteria. To achieve this goal, epidermal cell proliferation is to be controlled and the tissue-PAD seal protected from strain. Recognizing that epidermal migration is controlled by the intact dermis in the physiological state, we cultured dermal elements onto nanoporous polycarbonate. The relevant cell culture and nuclear bombardment techniques are now reproducible in our hands. Experiments with scaled-down PADs in rats confirmed the hypothesis that under appropriate conditions, cultivateddermal elements form a tight bond to the plastic substrate. Studies with full-scale PADs in miniature Yucatan swine arein progress and thus far are consistent with our hypothesis. During the coming year, a series of PADs (including some through which power will be transmitted) will be implanted for a two-year study.